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Nuclear medicine at UHL

Siemens Symbia Intevo Excel Gamma Camera at LRI
Siemens Symbia Intevo Excel Gamma Camera at LRI


In Nuclear Medicine we offer many different kinds of tests and treatments.

We use radiopharmaceuticals, which are small amounts of radioactive chemicals, sometimes referred to as radionuclides or radioisotopes.

These enable us to see the structure of organs and how they are working.

To watch an introdution video aboutMedical Physics and the Nuclear Medicine service, follow this video link and take a look at some of the things we do..

What will happen during my visit?

Most people visit the department as outpatients for diagnosis. You are given a small injection of radiopharmaceutical. This is no more painful than taking a sample for a blood test. It is very rare for anyone to experience side-effects.

Children are given anaesthetic cream before they have the injection. They will have a parent or carer with them and there are books, toys and someone to chat with. 

You may be asked to sit or lie still while images are taken. You will not be completely enclosed in the camera, it does not make any noise and a member of staff stays with you all the time. For other tests you may have some blood samples taken.

Some patients visit us for radioisotope therapy. This may be taken as a capsule or an injection, and occasionally requires a short stay in hospital. 

Nuclear medicine tests

Most nuclear medicine tests involve having pictures taken, these are called imaging procedures. Other tests involve giving blood samples throughout the day. These are called non-imaging procedures.

Imaging Procedures

The radiopharmaceutical given to you is chosen to target a specific part of the body. We can use this technique to look at a wide variety of organs and diseases. The exact area depends on what the doctor wants to look for.

You lie on the couch and the camera moves over or around your body. It will move close to you but will never touch you. The camera can see where the radiopharmaceutical has gone and creates a picture of the distribution of radiation in the body.

If there is more radiation in one area, this will show up as a darker area in the final image. This can be used to see how an organ functions, for example watching the radiopharmaceutical move through the kidneys.

Non-imaging procedures

The most common of these tests is Glomerular Filtration Rate, which is used to see how well the kidneys are functioning. A small amount of radiopharmaceutical is given to you as an injection. Blood samples are then collected.

The amount of radiation in the samples is counted and the results are put into a graph. The graphs are then used to determine whether the samples are within normal limits.

How are the radiopharmaceuticals given?

For diagnostic tests we give you a small amount of radioisotope. This is usually injected into a vein in your arm and goes to the specific part of your body that the doctor is interested in.

The radiation in the drug can then be detected by a camera, or a sample counting machine, to give images or graphs.

For therapy, we give larger amounts of radioisotopes which kill diseased cells. The therapy radioisotopes usually come in small capsules which you swallow.

What about the radiation dose?

We are all exposed to radiation from natural sources each year. The dose from many of our scans is small, around the average amount we are exposed to in a year. Most of it passes straight through you.

The benefit of having the investigation will far outweigh the risk of the radiation dose.  

Using radiation as a therapy

Nuclear medicine may also be used for therapy. Larger amounts of  radiopharmaceuticals are given to you and are designed to go to the diseased areas in the body. The radiopharmaceuticals used are different from those used for diagnosis as the radiation kills the diseased tissue without damaging healthy tissue.  

One example of radiation therapy is the use of radioactive iodine for the treatment of thyrotoxicosis, which is given in a tasteless capsule. This treatment may require you to stop taking some medication. There will also be some restrictions on contact with friends and relatives following the therapy. This will all be discussed with you in detail prior to the therapy.

For some therapies a short stay in hospital is required. However, more than 95% of our therapies are done on an outpatient basis. 

What equipment is used?

The most common piece of equipment used in nuclear medicine is called a gamma camera.

A gamma camera has two special detectors that can ‘see’ the radioactive drug inside the body, and the type of pictures taken will vary depending on what the doctors are looking for. These detectors must be positioned quite close to you so that good quality pictures can be taken. Sometimes the detectors remain still or move around you.

The radiation coming from the body passes through the detectors collimator, which is a thick sheet of lead with holes in a honeycomb pattern. This is to filter out the unwanted radiation and create a clear picture.

The radiation that passes through the collimator strikes a crystal and is converted to light, and then into a digital signal.

The gamma camera can then use the digital signal to determine where the radiation came from in the body, and how much radiation is present. This allows it to create a picture of the organ of interest. Sometimes the pictures are 3 dimensional, helping us to see even more detail.

Not all nuclear medicine tests use a gamma camera. Sometimes blood samples are taken instead. These are measured using a sensitive sample counter that detects the small levels of radioactivity in the samples.

More information:

If you would like any further information about any aspect of nuclear medicine please see our Further Information page or contact us.